Reflector



June 25, 1929. F. R. DURFEE ET AL 1,718,856

REFLECTOR Filed Dec. 25, 1927 In venbors FRANK H. UURF'EE THOMAS h. GUMM/NS AbCor-neqs Patented June 25, 1929.

UlTED STATES PATENT OFFICE.

FRANK R. DUE'LLFEE AND THOMAS K. CUMMINEJ, OF ST. PAUL, MINNESOTA.

REFLECTOR.

This invention relates generally to improvements in reflectors, and more parti cularly to reflectors adapted to be used. in connection with headlights of automobiles. The invention herein is a continuation in part, and improvement over a pending application of an invention for reflectors, lilcd June 23rd, 1926, and bearii'ig Serial Number 118,021. An object of the invention. is to provide a headlight reflector which eliminates that objectionable blinding glare coininon to the reflectors now in. use and which is the cause of man accidents.

A further object of the invention is to provide a parabolic reflector or a reflector of similar type, having only the upper portion of its reflecting surface modified to obtain a partial absorption of light rays. Other objects are to arrange the lightproducing portion of the lamp either at or always rear wardly of the focus of the reflector, and also to provide means for adjusting the bulb and positively preventing adjustment of said light-producing portion of the bulb to a point forwardly of the focus.

A further object of the invention is to provide a reflector which by concentration of light rays projected only from a lower highly reflective area will provide adequate illumination without glare; a further object to provide a reflector having approximately only its upper substantially one-half, modilied in such manner as to project mildly diffused light without glare but suflicient to obtain lateral and some forward lighting of the road.

Advantages will be set forth in a description of the drawin s forniin a iart of this application, and in said drawings:

Figure 1 is a vertical section through a parabolic mirror showing the upper portion of the surface modified for the purpose set forth herein, and indicating that the lowor surface portion only is highly reflective, and also illustrating the arrangement of the bulb either at or at some point rearwardly of the focus of the reflector, and further show ing adjustable means and means positively preventing adjustment of this means to place the light-producing portion of the bulb forwardly of the focus; and

Figure 2 is a front view corresponding to lfli rure 1.

For purposes of disclosure a headlight in an ordi ary parabolic tvpe of refleci illustrat -,5- llhis head 3 comprises the casing 1 having a reflector 2 secured there in and covered by the usual glass or lens The reflector and lens or glass are secured by the usual ring t, The focal point of the reflector is indicated at G, and the light-producing portion of the bulb is indicated at 7. It will be seen later that altl'iough this bulb is adjustable between the focus point and the surface of the reflector it can at no time be adjusted to a point fornuirdly of the focus.

A main feature of the invention consists in modifying that portion of the reflector which lies above a horizontal diameter drawn through the axis of the reflector, when the reflector in operative position. The remaining lower portion of the reflector is left highly reflective as usual, while the 1nodilication of the upper approximate one-half of the reflector, obtains a partial absorption of light rays sullicient to positively prevent a glare observable by others, approaching it. The elimination of glare, however, does not result in lack of suflicient illumination, but the modification of the upper surface merely subdues the light to prevent glare. This modification of the upper portion of the reflecting surface, the important feature of the invention. A convenient method of modifying the upper half of the reflecting surface of the reflector is to apply a coating of material which has power to partially absorb the light rays received thereon, and which may be referred to as light absorbent material. This material is indicated at 10, in section by a heavy line and in elevation by stippling.

The modification of the upper portion of the reflecting surface may be accomplished in a number of ways, either by the employment of a shield member applied as a cover to the surface and composed of material which will obtain the desired degree of modification, or a coating of a like substance ap-- plied by brush, or by some mechanical or electrochemical, modification of the metal of the reflector.

ln acti'lal tests made by the devices the relation of the light bulb to the focus, either forwardly or rcarwardly of the focus, has not seemed to modify the non-glaring efl'ect obtained by modifying the upper surface only of the reflector. However, theoretically there would be a difference in the character of the ill iination, if the bulb were allowed to p .witvardly of the focal cast For ment15. The forward edge of the element is bent as at 17 to provide a stop which,

as will be seen, acts to limit the forward motion of the element 16. The usual bulb contact members are generally indicated at 19. The adjusting means comprises a screw 20 ;having threaded engagement with an extension'21 of the sleeve 16 which extension passes through a slot 22 of the element 15.

The outer end of the screw is rotatably but non-translatably connected as at 23 to an extension 24 carried by the reflector. The

] screw 20 is of the ordinary headed type and has a screw driver slot 25 by which the screw is rotated. As the screw is rotated, the bulb is adjusted in a direction corresponding to the direction of rotation of the screw. In the drawing the element 16 is shown as engaging by its forward end against the stop. In this position the light-producing element 7 may be considered as being at the focus 6. As before stated, this element cannot be moved forwardly of the focal point.

The use of the device herein in actual test has proved that there is no glare under ordinary conditions of use and that adequate illumination is obtained laterally on both sides of the vehicle as well as forwardly of V the same.

Them'odification of only the upper part of the reflecting surface of the reflector re- :duces the reflection from the upper portion to such an extent that it is only the rays reflected by the lower portion which act to give a distant illumination of are road.

The use of this device in actual test has furthermore proved that more adequate and efl'ective illunnnation is obtained when driv- "ing through fog or rain, because the mildly difl'used light emanating from the upper portion does not produce prismatic or mirrored reflections from the globules of moisture, within the range of light reflected from said upper portion. The strong beam of light from the lower or hi ghly reflective portion is projected upon the roadway where needed.

\Ve claim as our invention:

1. A parabolic reflector having its upper half modified to obtain only partial absor tion of light rays and its lower half highly reflective, a source of light for illuminating the reflector and means for adjusting said light Source towards or away from the focus of said reflector, said means com u'ising an extension on the rear of said reflector, a tubular member having a stop on its inner end and inserted in the rear of said reflector and a socket in said tubular member having an extension thereon, and an adjusting means connected, with the extension on the reflector and cooperating with the extension on the socket to adjust the socket towards and away from the focus of the reflector, the stop serving to prevent adjustment of the source of light forward of the reflector focus.

2. A parabolic reflector having its upper portion modified to absorb light rays and its lower part highly reflective, a source of light, a tubular member extending through the rear of said reflector and a socket member therein, the tubular member having a flange at its inner end for preventiin the source of light from being adjusted in front of the reflector focus.

In witness whereof, we have hereunto set our hands this 20th day of December, 1927.

FRANK R. DURFEE. THOMAS K. CUMMlNS. 

